Document FR-2 886 384 describes an air vent which has adjustment of the orientation and flow rate and which comprises an air flow conduit having a chamber which forms a spherical segment, a profile-member having dimensions which are substantially less than those of the chamber, and a ring whose outer surface forms a sphere portion having the same radius as the spherical segment of the chamber; the ring is provided with arms carrying the profile-member by means of cooperation with grooves of the profile-member, which grooves are orientated practically in the flow direction of the air flow. In this manner, the profile-member can be rotated relative to the chamber of the conduit owing to the ring sliding against the spherical segment. The profile-member can further be moved in translation relative to the ring without the ring being moved in relation to the chamber.
In one embodiment, it is indicated that the profile-member can be pushed towards the inlet of the conduit so that it forms a stopper of the conduit.
FIG. 1 illustrates such an air vent having a conduit 10 which delimits a spherical segment, in contact with which there is provided a ring 26 which has arms 28 having an end 31 which can slide in a longitudinal groove 30 which is formed in the profile-member 18. The profile-member 18 has a rear surface 22 which is near the inlet 12 of the conduit and which carries a lip 44 which may move into contact with a portion 46 of the conduit 10 which is remote from the outlet 14 and in the region of which the profile-member may be gripped by means of a projection 24 which forms a holding member.
It became apparent that, as indicated in FIG. 2, when the profile-member 18 is inclined relative to the flow direction of the air flow, it was not possible to obtain complete contact of the profile-member 18 with the inlet 12 of the conduit 10. Consequently, when the user pushes the profile-member inwards by means of the projection 24, when the member 18 arrives at the end of travel, the surface 22 moves into contact with one side of the conduit 10 whilst the opposite side leaves a substantial space for the flow of air. In practice, in such an inclined position, the user does not obtain zero flow.
So that the flow rate of the air vent is zero, it is necessary for the user to position the translation direction of the profile-member in alignment with the axis of flow of air or the axis of the air vent, but there is no indication at all to the user that he must carry out such an operation.